My 2008 Honda Accord with in dash GPS started cycling on and off while turning the radio on and off. I had put some windows down and back up while the radio was on and the GPS turned itself on and turned the radio off. It appears to do it now when the car is idling but not on the highway. It sent a shudder through the car when stopped at a light and turned the radio off and the GPS on today. Any thoughts as to what is going on and how much it should cost to repair?